title: Nitroglycerin 0.4% ointment vs placebo in the treatment of pain resulting from chronic anal fissure: a randomized, double-blind, placebo-controlled study.
abstract: BACKGROUND
  Complications of chronic anal fissure (CAF) treatments are prompting interest in lower-risk therapies. This study was conducted to compare nitroglycerin (NTG) 0.4% ointment with placebo for pain associated with CAF.
  
  
  METHODS
  In this randomized, double-blind, placebo-controlled trial, patients with one CAF and moderate-to-severe pain (≥50 mm on a 100 mm visual analog scale [VAS]) received 375 mg NTG 0.4% (1.5 mg active ingredient) or 375 mg placebo ointment applied anally every 12 hours for 21 days. The primary end point was change from baseline VAS score in 24-hour pain averaged over days 14-18. Review of data from patients who withdrew early was blinded to treatment. To control for the confounding effects of analgesics, all patients received 650 mg acetaminophen for headache prophylaxis before each application.
  
  
  RESULTS
  A total of 247 patients were enrolled (NTG, n = 123; placebo, n = 124). The prespecified baseline observation carried forward (BOCF) analysis found no significant difference between groups; however, a last observation carried forward (LOCF) analysis showed a significant advantage for NTG. A post hoc analysis (LOCF/BOCF hybrid) demonstrated a significant adjusted mean difference of -7.0 mm in favor of NTG 0.4% (95% CI -13.6, -0.4; P = .038). Headache was the most common adverse event in the NTG (69.9%) and placebo (47.6%) groups.
  
  
  CONCLUSIONS
  This was the first placebo-controlled study that also controlled for the confounding effects of analgesics used to treat NTG-induced headache. In patients with moderate-to-severe CAF pain, NTG 0.4% ointment effectively reduced CAF pain compared with placebo.
  
  
  BACKGROUND
  ClinicalTrials.gov, NCT00522041.
authors.forename: Scott M
authors.initials: SM
authors.lastname: Berry
authors.forename: Charles F
authors.initials: CF
authors.lastname: Barish
authors.forename: Raj
authors.initials: R
authors.lastname: Bhandari
authors.forename: Gemma
authors.initials: G
authors.lastname: Clark
authors.forename: Gregory V
authors.initials: GV
authors.lastname: Collins
authors.forename: Julian
authors.initials: J
authors.lastname: Howell
authors.forename: John E
authors.initials: JE
authors.lastname: Pappas
authors.forename: Dennis S
authors.initials: DS
authors.lastname: Riff
authors.forename: Michael
authors.initials: M
authors.lastname: Safdi
authors.forename: Ann
authors.initials: A
authors.lastname: Yellowlees
mesh_terms: D000082:Acetaminophen / Q000627:therapeutic use; D000293:Adolescent; D000328:Adult; D000368:Aged; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D004311:Double-Blind Method; D005260:Female; D005401:Fissure in Ano / Q000150:complications*; D006261:Headache / Q000139:chemically induced / Q000517:prevention & control; D006801:Humans; D008297:Male; D008875:Middle Aged; D005996:Nitroglycerin / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D009824:Ointments; D010146:Pain / Q000188:drug therapy* / Q000209:etiology; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D018712:Analgesics, Non-Narcotic; D009824:Ointments; D000082:Acetaminophen; D005996:Nitroglycerin